Scheduling data transmissions between a mobile terminal and a base station in a wireless communications network

ABSTRACT

A method of scheduling wireless data transmissions between a mobile terminal and a base station using multiple system carrier signals is disclosed. The method comprises receiving ( 101 ) in the mobile terminal information from the base station indicating available system carriers and transmitting from the mobile terminal information indicating the terminal&#39;s capability to handle non-contiguous system carriers; detecting ( 102 ) at least one dynamic parameter indicative of the terminal&#39;s current capability to handle non-contiguous system carriers; determining ( 103 ) from the dynamic parameter whether a situation has occurred in which the terminal&#39;s capability to handle non-contiguous system carriers has changed; transmitting ( 104 ), in such case, a connection release request to the base station; and transmitting ( 105 ) a connection setup request and information indicating the terminal&#39;s changed capability to handle non-contiguous system carriers to the base station. Thus system carriers that can be handled by the terminal in the present situation can be allocated.

TECHNICAL FIELD

The invention relates to methods and devices for scheduling datatransmissions between a mobile terminal and a base station in a wirelesscommunications network arranged for the transmission of multipleindependently scheduled component carrier signals.

BACKGROUND

With each generation, wireless communication systems are characterizedby ever-higher data rates. While some increase in data rates may beattributed to improvements in modulation, coding, and the like,significant increases in data rates generally require higher systembandwidths. For example, the International Mobile Telecommunications,IMT, advanced (a proposed fourth generation (4G) wireless communicationsystem), mentions bandwidths up to 100 MHz. However, the radio spectrumis a limited resource, and since many operators and systems compete forlimited radio resources, it is unlikely that 100 MHz of contiguousspectrum will be free for such systems.

One approach to increasing bandwidth requirements in limited, fragmentedspectrum is to aggregate non-contiguous spectrum. From a baseband pointof view, this can effectively increase the system bandwidth sufficientlyto support up to 1 Gb/s, a throughput requirement for 4G systems.Transmitting data in non-contiguous parts of the spectrum alsointroduces flexibility, as spectrum utilization may be adapted toexisting spectrum use and geographical position. Additionally, differentmodulation and coding schemes may be advantageously applied to differentportions of the spectrum.

A possible evolution of current cellular systems, such as the 3GPP LongTerm Evolution (LTE), to support non-contiguous spectrum is to introducemultiple component carriers or multiple channels. In such amulti-channel or multiple component carrier system, each separateportion of spectrum may be considered an LTE system. Multi-channeltransmission is likely to be a principal part of the further releases of3G LTE targeting ITU IMT-Advanced capabilities. A mobile terminal foruse in such a system will be capable of receiving multiple componentcarriers, of different bandwidths, and transmitted at different carrierfrequencies. Also High-Speed Packet Access (HSPA) systems can usemultiple bands, e.g. dual carrier (downlink) and dual cell (uplink). Inthe following, the general term “multiple system carrier” is used.

US 2007/007090 discloses a multi-carrier communication system in whichradio resources are distributed between a plurality of access terminals.The carriers assigned to an access terminal are determined by thenetwork based on scheduling information received from the accessterminal. The scheduling information may include data requirements,Quality-of-Service requirements, available transmit power headroom, thelocation of the access terminal, or hardware constraints associated withthe access terminal. This disclosure does not relate to the use ofnon-contiguous bandwidths.

The design of a mobile terminal supporting multiple non-contiguoussystem carriers is a non trivial task. The aggregated spectrum approachimplies that the radio receiver architecture for such a mobile terminalwill become more complicated than a terminal only capable to receivecontiguous system band-widths. One reason for this is that the front endradio needs to be able to suppress blocking signal in between thespectrum “chunks”. Different kinds of radio architecture can be used forhandling this problem; however, they typically have drawbacks comparedto standard contiguous system receivers in terms of current consumption.Therefore there is a need for an efficient non-contiguous multi-carriersystem design taking into account the challenges in the mobile terminalfront end receiver design.

SUMMARY

Therefore, it is an object of embodiments of the invention to provide aflexible method of scheduling data transmissions, which is moreefficient and takes the mobile terminal's current ability to handlenon-contiguous system carriers into account.

According to embodiments of the invention the object is achieved byusing a method of scheduling data transmissions between a mobileterminal and a base station in a wireless communications networkarranged for the transmission of multiple system carrier signals, eachsystem carrier providing for the transmission of signals in apredetermined bandwidth around the carrier.

The method may comprise the steps of receiving in the mobile terminalinformation from said base station indicating available componentcarriers, and transmitting from said mobile terminal to said basestation information indicating the mobile terminal's capability tohandle component carriers having non-contiguous bandwidths; detecting inthe mobile terminal at least one dynamic parameter indicative of themobile terminal's current capability to handle non-contiguous systemcarriers; determining in the mobile terminal from said at least onedynamic parameter whether a situation has occurred in which the mobileterminal's capability to handle non-contiguous system carriers haschanged; transmitting, if such a situation has occurred, a connectionrelease request from said mobile terminal to said base station; andtransmitting a connection setup request and information indicating themobile terminal's changed capability to handle non-contiguous systemcarriers from said mobile terminal to said base station.

By doing a connection release and then a connection setup using anothercapability reflecting the changed situation determined from the dynamicparameter, it is ensured that the base station allocates system carriersthat can be handled by the mobile terminal in the present situation.

In some embodiments the system carrier signals may be transmitted in aThird Generation Long Term Evolution system or in a High-Speed PacketAccess system.

In one embodiment the method further comprises the step of selecting theat least one parameter from the group of parameters consisting of aparameter indicative of a charging level of a battery in the mobileterminal, a parameter indicative of a level of transmission power fromthe mobile terminal required to achieve a predetermined quality level ofdata transfer from the mobile terminal and a parameter indicative of alevel of base band processing capability in the mobile terminal.

By letting the mobile terminal control the number of system carrier touse in respect to a parameter indicative of a charging level of abattery in the mobile terminal, a longer battery lifetime may beachieved. This may be done by limiting the use of multiple componentcarriers when the battery charging level is low, thereby saving thepower needed to support multiple component carriers. Additionally asimpler design of the mobile terminal may be used since there is no needfor supporting multiple system carriers at a low battery voltage.

By letting the parameter be indicative of a level of transmission powerfrom the mobile terminal, to achieve a predetermined quality level ofdata transfer, a simpler design of the mobile terminal may be used,since the mobile terminal does not have to support multiple systemcarriers when transmitting with a high power. This may be achieved bylimiting the number of system carriers used when transmitting with ahigh power.

By letting the parameter be indicative of a level of base bandprocessing capability in the mobile terminal a more efficient use of theprocessing resources in the mobile terminal may be achieved. This may bedone by limiting the number of system carriers used when the processingresources in the mobile terminal is scarce.

In one embodiment the method further comprises the steps of detectingthe occurrence of a system carrier event triggered by one of theparameter levels passing a predefined threshold; and performing the stepof determining whether a situation with changed capability to handlenon-contiguous system carriers has occurred when a system carrier eventis detected.

By controlling the use of multiple system carriers in respect to anevent triggered by the passing of a predetermined threshold by one ofthe parameter levels, an easy implementation of the method in a mobileterminal is made possible.

In one embodiment the method further comprises the step of determiningthe mobile terminal's changed capability to handle non-contiguous systemcarriers in dependence of said detected system carrier event.

In one embodiment the changed capability is determined in dependence ofsaid detected system carrier event by means of a look up table.

In one embodiment the steps of transmitting a connection releaserequest, a connection setup request and information indicating themobile terminal's changed capability use a Radio Resource Control, RRC,signalling protocol.

Some embodiments of the invention relate to a mobile terminal configuredto schedule data transmissions between the mobile terminal and a basestation in a wireless communications network arranged for thetransmission of multiple system carrier signals, each system carrierproviding for the transmission of signals in a predetermined bandwidtharound the carrier. The mobile terminal is configured to receiveinformation from said base station indicating available system carriers,and transmit to said base station information indicating the mobileterminal's capability to handle non-contiguous system carriers; detectat least one dynamic parameter indicative of the mobile terminal'scurrent capability to handle non-contiguous system carriers; determinefrom said at least one dynamic parameter whether a situation hasoccurred in which the mobile terminal's capability to handlenon-contiguous system carriers has changed; transmit, if such asituation has occurred, a connection release request to said basestation; and transmit a connection setup request and informationindicating the mobile terminal's changed capability to handlenon-contiguous system carriers to said base station.

Embodiments corresponding to those mentioned above for the method alsoapply for the mobile terminal.

Some embodiments of the invention relate to a computer program and acomputer readable medium with program code means for performing themethod described above.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described more fully below withreference to the drawings, in which

FIG. 1 is a frequency plot showing multiple component carriers;

FIG. 2 a is a frequency plot showing the spectrum leakage whentransmitting multiple component carriers with low power;

FIG. 2 b is a frequency plot showing the spectrum leakage whentransmitting multiple component carriers with high power;

FIG. 3 a is a frequency plot showing the amplitude of a low energyinterference signal positioned between two component carriers prior tofiltration;

FIG. 3 b is a frequency plot showing the amplitude of a low energyinterference signal positioned between two component carriers afterfiltration;

FIG. 4 a is a frequency plot showing the amplitude of a high energyinterference signal positioned between two component carriers prior tofiltration;

FIG. 4 b is a frequency plot showing the amplitude of a high energyinterference signal positioned between two component carriers afterfiltration; and

FIG. 5 is a flow chart of a method of scheduling data transmissionsbetween a mobile terminal and a base station; and

FIG. 6 is a functional block diagram of a mobile terminal.

DETAILED DESCRIPTION OF EMBODIMENTS

In order to achieve higher bandwidths, e.g. up to 100 MHz, in wirelesscommunications networks non-contiguous spectrum can be aggregated. FIG.1 depicts an example of aggregation of system carriers to achievegreater bandwidth. It may be noted that the left-most system carrier iswell spaced-apart in frequency to the other system carriers. It willexperience, and cause, only a small amount of Inter carrier interferencedue to the wide carrier spacing. However, the two right most systemcarriers are not as well spaced apart in frequency.

In a spectrum aggregated or multi-channel system as is discussed herein,several frequency bands, contiguous or non-contiguous, may be allocatedfor the communication with one mobile terminal. The modulation andaccess format within the band could be of any kind, e.g., orthogonalfrequency division multiplexing (OFDM), single-carrier frequencydivision multiplexing (SC-FDMA), code-division multiple access (CDMA)etc. In this application, we denote such a system “multiple componentcarrier system” or “multiple system carrier system”. In this context,one channel is referred to as one “component carrier” or one “systemcarrier”. It may also be noted that this type of system in somepublications is called “multi-carrier”, however, the term componentcarrier or system carrier is used here to avoid confusion with OFDMsub-carriers.

In the following, a Third Generation Long Term Evolution (3G LTE) systemis used as an example for explaining the invention. However, it is notedthat the invention is not limited to such a system, but can be used aswell in other systems. One example of another system, where theinvention can be used, is a High-Speed Packet Access (HSPA) system, inwhich dual-carrier can be used in the downlink and dual-cell can be usedin the uplink. In a new release HSPA will be extended to 4 carrier or 4cell HSPA.

Thus a system carrier can be a 3G LTE component carrier or a HSPA dualcarrier. It is noted that a non dual-cell HSPA (i.e. single HSPAcarrier) capable terminal is capable to connect on such a system (HSPA)carrier, and that a non component carrier LTE (i.e. single carrier LTE)terminal is capable to connect on such a system (LTE) carrier.

Since 3G LTE uses the term “component carrier” this term is used in thefollowing description for convenience instead of the more general term“system carrier”.

This invention describes methods and devices for handling problems withmulti-component carrier support in case of some kind of overloadsituation. For instance, depending on the battery status, the neededtransmit power, real-time processing problem etc, there can besituations where the mobile terminal could not support multi-componentcarrier according to it's mobile terminal capability. In uplink it coulde.g. be hard to fulfil spectrum leakage requirements, while in downlinkit can be hard to fulfil blocking requirements. Different kind of radioarchitecture can be used for handling this problem, but they typicallyhave drawbacks compared to standard continuous system bandwidthreceivers in terms of current consumption.

FIGS. 2 a and 2 b illustrate a situation with uplink transmission from amobile terminal on multiple component carriers.

FIG. 2 a shows frequency leakage when transmitting with relatively lowpower from a mobile terminal to a base station. The transmit power levelis typically chosen based on a predetermined quality level requirement.Closed power loops are commonly used to adjust the transmit power. Theloops function by monitoring, in the base station, the quality level ofthe transmission. If the quality level drops below a predeterminedthreshold, a control signal is sent from the base station to the mobileterminal, which in return increases the transmit power. Reversely, Ifthe quality rises above a predetermined threshold, the base stationsignals to the mobile terminal which then decreases the transmit power.

Two component carriers 301, 302 are shown. Nonlinearities in thetransmitter and RF power amplifier result in intermodulation distortion,this leads to frequency leakage. To enable other users to use thebandwidth positioned outside the bandwidths of the used componentcarriers, strict frequency leakage requirements apply on mobileterminals. 303 shows the frequency leakage of the two component carriers301, 302, and 304 shows the leakage requirement of the mobile network.The frequency leakage 303 of the two component carriers 301, 302 isbelow the leakage requirement 304 when the transmit power of thecarriers is low.

FIG. 2 b shows frequency leakage when transmitting with a higher powerfrom the mobile terminal to a base station. Again, two non-contiguouscomponent carriers 305,306 are shown. They are positioned at the samefrequencies as the two component carriers 301,302 in FIG. 2 a, howeverdue to the increased transmit power their amplitude is higher. Thespectrum leakage 307 of the two carriers is now above the spectrumleakage requirement of the mobile network. Using a more lineartransmitter and RF power amplifier is a possible way to mitigate this.However, highly linear components generally consume more power andincrease the complexity and cost of the mobile terminal.

Thus it can be advantageous to control the number of component carriersbased on the needed transmit power of the individual carriers. One wayof doing this is to decrease the number of component carriers used, whenthe transmit power is high, i.e. above a predefined threshold.Alternatively, use of component carriers with a narrow bandwidth may belimited, when transmitting with high power. This will enablemulti-carrier support on mobile terminals without the need of costlyhardware and with reasonable power consumption.

Similarly, it can be advantageous to control the number of componentcarriers based on the state of charge of the battery in the mobileterminal. This may be done by decreasing the number of componentcarriers used, when the state of charge of the battery is low, therebyachieving both multi carrier support and a long battery life time,without the need of a complex and expensive architecture in the mobileterminal.

The number of component carriers used may also be controlled by a powermanagement system functioning as a dynamic parameter. The powermanagement system may function by estimating the power consumption ofsupporting multiple component carriers and determine the number ofcarriers to use in relation to the estimated power consumption. This maybe done by limiting the number of component carriers used when the powerconsumption for supporting multiple component carriers is high. Thestate of charge of the battery in the mobile terminal may also be usedas an input to the power management system. By using a power managementsystem a longer battery life time is achieved. Thereby multiplecomponent carriers may be supported only in situations where the powerconsumption for supporting them is relative low.

FIGS. 3 a, 3 b, 4 a and 4 b illustrate a situation with downlinktransmission to a mobile terminal on multiple component carriers.

FIG. 3 a shows a frequency plot of an interference signal 502 withrelatively low energy positioned between two component carriers 501,502prior to filtration in a mobile terminal. 504 is a threshold showing theability of the filters in the mobile terminal to block out interferencesignals. The threshold is determined by the quality of the filters inthe mobile terminal. The interference signal 502 has an amplitude thatis lower than the threshold 504. FIG. 3 b shows a frequency plot of thesame situation as depicted in FIG. 3 a, after filtration in the mobileterminal. The power of the interference signal has been minimized to aninsignificant level, and a good quality of service is achieved for thetwo component carriers 501,502.

FIG. 4 a shows a frequency plot of an interference signal 602 with ahigher energy positioned between the two component carriers 601,602prior to filtration in a mobile terminal. 604 is a threshold showing theability of the filters in the mobile terminal to block out interferencesignals. The amplitude of the interference is in this situation higherthan the threshold 604. FIG. 4 b shows a frequency plot of the samesituation as depicted in FIG. 4 a after filtration in the mobileterminal. The power of the interference signal has been lowered, but itremains relatively high compared to the amplitude of the two componentcarriers 601,602 resulting in a poor quality of service of the carriers.This can be corrected by using high performance filters with a higherthreshold; however this will again both increase the total powerconsumption and increase the overall cost of the device.

Thus it can be advantageous to control the number of used componentcarriers based on the power of interference signals. This may beachieved by limiting the use of multi carrier components when highenergy interference signals are present, thereby achieving good multicarrier support in the most common case, when no high energyinterference signals are present, without the need of costly hardware tocope high energy interference signals.

Mobile terminals have transformed from being simple communication toolsinto being a fully operational transportable computer system, providinga range of different applications such as audio and movie applications,maps, dictionaries and games. This evolution has increased the need forprocessing power in mobile terminals. Multi carrier component supportfurther increases the overall processing load of the mobile terminal.

Therefore, complicated applications might be processed slower when multicarrier components are used, resulting in a decreased user experience.Thus it can be advantageous to control the number of component carriersused in relation to the processing load of the mobile terminal. This canbe achieved by using fewer component carriers when processingcomplicated applications, thereby securing a faster processing ofcomplex application and an increased user experience.

FIG. 5 shows a flow chart of an embodiment of the present invention, Instep 101 the mobile terminal is connected to a multi component carriernetwork node. This may be achieved by using a cell search procedure. Themobile terminal then receives information related to the availablecomponent carrier possibilities of the multi component carrier cell.This information may include information related to the bandwidth andcarrier frequencies of the component carriers. The number of availablecomponent carriers may be any number, including the special case whenonly a single component carrier is available. The mobile terminal thendetermines a subset of the available component carriers to use fortransmitting and receiving data from and to the multi component carriercell, i.e. the mobile terminal's capability to handle multiple componentcarriers, including its capability to handle non-contiguous componentcarriers, and it informs the multi component carrier cell about thiscapability; typically via standard Radio Resource Control (RRC)signaling. The choice may be based on the physical resources of themobile terminal. The subset does not have to be a proper subset, meaningthat the chosen subset may include all the possible component carriersreceived from the multi-carrier cell. The subset may also include just asingle component carrier.

Next, in step 102 the mobile terminal monitors dynamic parametersindicative of its current capability to handle non-contiguous componentcarriers, and from the detected parameters it is determined in step 103whether a situation has occurred in which the mobile terminal'scapability to handle non-contiguous component carriers has been changed,i.e. whether a component carrier support event has occurred. Asdescribed above, such events or situations may relate to parameters suchas the battery level of the mobile terminal, the transmit power of themobile terminal, the processing load of the mobile terminal, energy ofinterference signals, or data transfer requirements of applications onthe mobile terminal. For instance, in case of low battery or high neededtransmit power it could be difficult for the mobile terminal to supportmulti-component carrier transmission in uplink and/or downlink. Inuplink it could e.g. be hard to fulfil spectrum leakage requirements,while in downlink it could e.g. be hard to fulfil blocking requirements.Another example could be some kind of overload in the real timeprocessing in the base-band, making a large downlink reception overmultiple component carriers risky in terms of risk for timing mismatch,which then in the end might give rise to a dropped connection.

The occurrence of a component carrier event is typically triggered bythe level of one of the dynamic parameters passing a predefinedthreshold. However, it is noted that there may well be more than onethreshold for a given parameter so that the capability of handlingnon-contiguous component carriers can be reduced in steps. Similarly, acomponent carrier event may also be triggered by a combination ofparameters passing their individual predefined thresholds. Thecombination may be any combination of the following parameters: thebattery level of the mobile terminal, the transmit power of the mobileterminal, the processing load of the mobile terminal, energy ofinterference signals, or data transfer requirements of application onthe mobile terminal. E.g. a component carrier event may be triggered bya combination of low battery level and high needed transmit power.

If an event is triggered, i.e. a situation with reduced capability tohandle non-contiguous component carriers has occurred, then the mobileterminal in step 104 does a connection release, i.e. the mobile terminalis forced down to idle mode, and then in step 105 it makes a connectionsetup using another mobile terminal capability. The new capability mayalso include the case where only a single component carrier can be used.The connection setup/release is done according to prior art protocols.Which capability to choose depends on the component carrier eventtriggered, and such event to capability information could be stored in alook up table in the mobile terminal. The process can then continue atstep 102. Once a new component carrier event (for instance normaloperation possible) is triggered, the mobile terminal does a newconnection release and connection setup with a new mobile terminalcapability, which may be higher (for instance maximum allowed) or loweraccording to the triggered component carrier event.

It is noted that in LTE and LTE advanced fast connection setup andconnection release protocols have been introduced (in the order of 100ms instead of seconds, as it is in WCDMA/HSPA). By utilizing these fastconnection setup and release protocols in LTE and LTE advanced, forsaving power/reducing heat in overload situations, the user experiencein terms of service interruption is minimized, and at the same time theprocedure neither needs any standardization changes nor adaptationmechanisms that might hurt the spectral efficiency of the cellularsystems. However, the proposed solution could also be used in currentWCDMA systems, including HSPA, without any standard changes. However, inthis case the connection setup protocol is slower, which can make aservice interruption visible for the user.

FIG. 6 shows a functional block diagram of a mobile terminal 701configured to schedule data transmissions between the mobile terminaland a base station in a wireless communications network using theprinciples of the present invention. The mobile terminal comprises anantenna 702 for communicating with the base station using radiofrequency signals. The radio frequency signals from the antenna isreceived in the radio frequency block 703, which has a reception partand a transmission part, and then processed in the base-band processingblock 704. Information from the base station indicating availablecomponent carriers is then determined and stored in the availablecomponent carriers unit 705. In block 706 the mobile terminal detects atleast one dynamic parameter indicative of the mobile terminal's currentability to handle non-contiguous component carriers. The parameters aredescribed above.

The control block 707 determines from the at least one dynamic parameterwhether a situation has occurred in which the mobile terminal'scapability to handle non-contiguous component carriers has been changed.As mentioned above, this is typically done by comparing the parametervalue with a predetermined threshold. If it is determined that such asituation has occurred, the control block 707 transmits a connectionrelease request and subsequently a connection setup request with anothercapability to the base station through the baseband processing block 704and the transmitter part of the radio frequency block 703.

Although various embodiments of the present invention have beendescribed and shown, the invention is not restricted thereto, but mayalso be embodied in other ways within the scope of the subject-matterdefined in the following claims.

The invention claimed is:
 1. A method of scheduling data transmissionsbetween a mobile terminal and a base station in a wirelesscommunications network arranged for the transmission of multiple systemcarrier signals, each system carrier providing for the transmission ofsignals in a predetermined bandwidth around the carrier, the methodcomprising: receiving, in the mobile terminal, information from the basestation indicating available system carriers, transmitting, from themobile terminal to the base station, information indicating a capabilityof the mobile terminal to handle non-contiguous system carriers;detecting, in the mobile terminal, at least one dynamic parameterindicative of a current capability of the mobile terminal to handlenon-contiguous system carriers; determining, in the mobile terminal andfrom the at least one dynamic parameter, whether a situation hasoccurred in which the capability of the mobile terminal to handlenon-contiguous system carriers has changed; in response to determiningthat the capability of the mobile terminal to handle non-contiguoussystem carriers has changed, the mobile terminal both: transmitting aconnection release request to the base station; and transmitting aconnection setup request and information indicating the changedcapability of the mobile terminal to handle non-contiguous systemcarriers to the base station.
 2. The method according to claim 1,wherein said system carrier signals are transmitted in a ThirdGeneration Long Term Evolution system or in a High-Speed Packet Accesssystem.
 3. The method according to claim 1, further comprising selectingsaid at least one parameter from the group of parameters consisting of:a parameter indicative of a charging level of a battery in the mobileterminal; a parameter indicative of a level of transmission power fromthe mobile terminal required to achieve a predetermined quality level ofdata transfer from the mobile terminal; and a parameter indicative of alevel of base band processing capability in the mobile terminal.
 4. Themethod according to claim 3, further comprising: detecting theoccurrence of a system carrier event triggered by one of said parameterlevels passing a predefined threshold; and performing the step ofdetermining whether a situation with changed capability to handlenon-contiguous system carriers has occurred when a system carrier eventis detected.
 5. The method according to claim 4, further comprisingdetermining the changed capability of the mobile terminal to handlenon-contiguous system carriers in dependence of said detected systemcarrier event.
 6. The method according to claim 5, wherein the changedcapability is determined in dependence of said detected system carrierevent by means of a look up table.
 7. The method according to claim 1,wherein the steps of transmitting the connection release request, theconnection setup request and the information indicating the changedcapability of the mobile terminal use a Radio Resource Control, RRC,signalling protocol.
 8. A mobile terminal configured to schedule datatransmissions between the mobile terminal and a base station in awireless communications network arranged for the transmission ofmultiple system carrier signals, each system carrier providing for thetransmission of signals in a predetermined bandwidth around the carrier,the mobile terminal comprising: a reception circuit configured toreceive information from the base station indicating available systemcarriers; a transmission circuit configured to transmit, to the basestation, information indicating the capability of the mobile terminal tohandle non-contiguous system carriers; a detection circuit configured todetect at least one dynamic parameter indicative of the currentcapability of the mobile terminal to handle non-contiguous systemcarriers; and a control circuit configured to: determine, from the atleast one dynamic parameter, whether a situation has occurred in whichthe capability of the mobile terminal to handle non-contiguous systemcarriers has changed; in response to determining that the capability ofthe mobile terminal to handle non-contiguous system carriers haschanged, cause the transmission circuit to both: transmit a connectionrelease request to the base station; and transmit a connection setuprequest and information indicating the changed capability of the mobileterminal to handle non-contiguous system carriers to the base station.9. The mobile terminal according to claim 8, wherein the mobile terminalis configured to be used in a Third Generation Long Term Evolutionsystem or in a High-Speed Packet Access system.
 10. The mobile terminalaccording to claim 8, wherein the control circuit is further configuredto select said at least one parameter from the group of parametersconsisting of: a parameter indicative of a charging level of a batteryin the mobile terminal; a parameter indicative of a level oftransmission power from the mobile terminal required to achieve apredetermined quality level of data transfer from the mobile terminal;and a parameter indicative of a level of base band processing capabilityin the mobile terminal.
 11. The mobile terminal according to claim 10,wherein the control circuit is further configured to: detect theoccurrence of a system carrier event triggered by one of said parameterlevels passing a predefined threshold; and determine whether a situationwith changed capability to handle non-contiguous system carriers hasoccurred when a system carrier event is detected.
 12. The mobileterminal according to claim 11, wherein the control circuit is furtherconfigured to determine the changed capability of the mobile terminal tohandle non-contiguous system carriers in dependence of said detectedsystem carrier event.
 13. The mobile terminal according to claim 12,wherein the control circuit is further configured to determine thechanged capability in dependence of said detected system carrier eventby means of a look up table.
 14. The mobile terminal according to claim8, wherein the transmission circuit is further configured to transmitthe connection release request, the connection setup request andinformation indicating the mobile terminal's changed capability using aRadio Resource Control, RRC, signalling protocol.
 15. A computer programproduct stored on a non-transitory computer readable medium to scheduledata transmissions between a mobile terminal and a base station in awireless communications network arranged for the transmission ofmultiple system carrier signals, each system carrier providing for thetransmission of signals in a predetermined bandwidth around the carrier,the mobile terminal receiving information from the base stationindicating available system carriers, the computer program productcomprising computer program instructions that, when executed by aprocessor of the mobile terminal cause the mobile terminal to: transmit,to the base station, information indicating the capability of the mobileterminal to handle non-contiguous system carriers; detect at least onedynamic parameter indicative of the current capability of the mobileterminal to handle non-contiguous system carriers; determine, from theat least one dynamic parameter, whether a situation has occurred inwhich the capability of the mobile terminal to handle non-contiguoussystem carriers has changed; and in response to determining that thecapability of the mobile terminal to handle non-contiguous systemcarriers has changed, both: transmit a connection release request to thebase station; and transmit a connection setup request and informationindicating the changed capability of the mobile terminal to handlenon-contiguous system carriers to the base station.